COAL MEASURES.
The coal measures of Ohio, lying immediately west of the Ohio River, contain the same coal-seams which the corresponding measures contain on the opposite side in Pennsylvania, West and Kentucky. Opposite Pittsburg and Wheeling, the upper coals are found in Ohio, and of course all the lower coals. But to the north, and, in fact, all points towards the margins of the coal-field, the seams decrease in number, as they do in all coal-fields. The underlying seams always cover the greatest area, .while the upper seams are the most contracted, on a natural principle developed in all basin-formations. When the basin is deep and narrow, the dip of the measures or strata is great, and the respective areas occupied by the upper or lower measures do not differ greatly. But when the basins are shallow, or the dips of the measures very gentle and the basins very wide,—as in the present case,—the edges or outcrops of the lower seams are always of far greater extent than the upper seams, as may be seen exemplified in any conical hill where the strata are nearly horizontal. All this, of course, is plain enough to the practical; but we write for many who know little about horizontal formations, or stratification generally.
We may thus explain why there are five or six productive coal-seams, averaging from 20 to 30 feet of coal, in the eastern part of the Ohio deposits, and only one coal-seam in its western and northern portions, pro ductive of only three to five feet of workable coal. By far the largest amount of coal in Ohio is deposited in the seam B, which ranges from 4 to 10 feet in thickness and is productive of excellent coal generally. This
seam supplies most of the furnace-coal of Ohio, as it does in Pennsylvania. Towards the northern portions of the field it is used raw in the furnace, and found to answer a good purpose; but to the south it contains too much bitumen for this purpose, and requires to be coked.
Up to 1850, most of the Ohio blast-furnaces used charcoal; but perhaps the larger quantity of pig-iron is now produced with coke or raw coal. The same may be said of the locomotives which work the numerous railroads that traverse Ohio: they now use coal instead of wood.
There were 50 furnaces in blast in Ohio during 1864, and of these 20 may be stated as using coke or raw coal; and, as coke or coal furnaces are always larger than charcoal furnaces, those using mineral fuel must have produced more iron than those using charcoal. Large quantities of coal are mined and shipped down the Ohio, or sent by rail to Lake Erie, and from thence to the various ports on the Lakes.
The amount of coal raised in Ohio is stated to be one million tons per annum: we think this, however, is much below the mark, and may be about the amount shipped, or used in the furnaces, mills, cities, and loco motives, but evidently does not include the coal used for domestic purposes in the interior towns and villages. Ohio is a populous State, and wood is becoming scarce, and not available for fuel near her fast-growing towns and villages.